Portal box

ABSTRACT

A kit for raising and increasing wheel torque of an off road four wheel vehicle comprising four portal boxes, each portal box being associated with an individual one of the vehicle wheels, the portal boxes enclosing identical gear sets and associated bearings, each portal box being adapted to receive the output of an axle constant velocity joint and having an output shaft projecting therefrom, a set of four metal backing plates for joining the portal boxes to the suspension arms of the vehicle, the backing plates being substantially identical, the backing plates each having inwardly extending mounting brackets for attaching to upper and lower suspension arm parts.

BACKGROUND OF THE INVENTION

The invention relates to a novel portal box construction for use inlight off road vehicles.

PRIOR ART

Off road vehicles in the form of ATV's (all-terrain vehicles) and UTV's(utility task vehicles) are produced by numerous manufacturers.Purchasers and users of these vehicles frequently desire to fit themwith larger tires to give them greater agility in traversing roughterrain. To fit larger tires on these vehicles, it is common to installa lift kit to raise the vehicle body to make room for the larger tiresand to increase ground clearance. Typically, a lift kit will adverselyaffect constant velocity (CV) joint angles and necessitate replacementof the original equipment axles, including CV joints. Even with theseupgrades, steering geometry can be compromised and bump steer, forexample, can be introduced. Still further, the final drive ratiomeasured as available force at the thread surface of the oversize tiresis reduced in proportion to the size increase. The foregoing reveals aneed for an aftermarket system to mount oversize wheels on off roadvehicles that avoids the disadvantage of ordinary lift kits.

SUMMARY OF THE INVENTION

The invention provides a portal box system for light off road vehiclesthat is simple, low in cost, and readily adapted for use on vehicles ofdifferent manufacturers. The disclosed portal box system comprises auniversal backing plate and a narrow profile two-part housing in whichis mounted a torque and height increasing gear train. The same backingplate with proper brackets attached can be used at all four wheels of aspecific vehicle and with different sets of brackets on severaldifferent vehicles. The same left and right housings are used for frontand rear wheels of a vehicle to which the system is applied. The samegear train can be used at all of the wheels and only the input gear maybe modified to suit a particular brand of vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a light off road vehicle to which theinvention is applied;

FIG. 2 is a somewhat schematic exploded isometric view of a portal boxsystem employing the invention;

FIG. 3 is a somewhat schematic cross-sectional view at one axle of aportal box system constructed in accordance with the invention;

FIG. 4 is a fragmentary perspective view of a left front axle andsuspension arms of the vehicle of FIG. 1 on which is assembled a backingplate and associated suspension mounting brackets; and

FIG. 5 is a view similar to FIG. 4 of the left rear axle, associatedbacking plate and corresponding mounting brackets.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention is useful in lifting the chassis and increasing the wheeltorque of light off road four-wheel drive vehicles such as the UTVillustrated in FIG. 1. The illustrated vehicle is originallymanufactured by John Deere and marketed as a Model RSX 850i. It will beappreciated by those skilled in the art that the invention is applicableto vehicles of other manufacturers.

The invention provides a portal box system, available as a kit, thatreplaces a vehicle's original wheel hub assemblies. The kit can includefour portal boxes 10 and associated backing plates 11. FIGS. 2 and 3illustrate a typical portal box 10 and backing plate 11. The backingplate 11 at each wheel 12 (FIG. 1) can be identical or essentiallyidentical. Each backing plate 10 is provided with upper and lowermounting brackets 16, 17. Preferably, the backing plate 10 is a steelplate, for example, ¼ inch thick. The brackets 16, 17, made of ½ inchsteel plate, for example, are attached to the plate 11 preferably bywelding.

Referring to FIG. 4, the upper bracket 16 can have a hole 18 forattaching an upper ball joint 19 and a hole 20 (FIG. 2) for attaching asteering rod end 21. Similarly, the lower bracket 17 has a hole 22 forsecuring a lower ball joint stud 23.

Referring to FIG. 5, at a rear axle, an upper bracket 26 has a hole 27for receiving an upper ball joint stud 28 and a lower bracket 29 has ahole for receiving a lower ball joint stud. A third bracket 31 welded tothe backing plate 11 receives the stud of a rod end of a track bar 32.

The backing plate 11 and associated mounting brackets are preferablyplanar elements cut or stamped from steel plate. It will be seen thatthe backing plate 11, which has four major perimeter edges that lie in acommon imaginary rectangle, can be reversed side-for-side to serve bothsides of the vehicle 5. The backing plate 11 has the same orientation oneach side of the vehicle 5. Similarly, the mounting brackets 16, 17, 26,29 and 31 can be reversed when they are attached to a respective backingplate 11 to serve the opposite side of the vehicle 5.

A large clearance hole 36 is cut in the backing plate 11 for the outputshaft of the CV joint of the vehicle's axle or half shaft. A smallclearance hole 37 is provided in the backing plate 11 for access to alubricant fill plug in an inboard face of the portal box 10. Four spacedportal box mounting bolt holes 38 are provided about the periphery ofthe plate 11.

The portal box housing comprises a case 41 and a cover 42. Preferably,both the case 41 and cover 42 are machined metal bodies, preferably ofhigh strength 6061 aluminum. The illustrated case 41 is machined from asolid block of spaced aluminum; alternatively, the case can be cast orforged to a rough configuration, and then finish machined. The case 41has a rear or inboard main wall 43 and an integral peripheral wall 44. Aface 45 of the peripheral wall 44 lies in a plane parallel to the planeof the main wall 43. The peripheral wall 44 forms a space for receivingmeshed spur gears 46-48. Circular recesses 51, 52 are formed in aninside face of the case wall 43 to receive and support bearings 53, 54that rotationally support respective gears 46-48. A recess and bearingfor a gear 47 exists in the wall 43 but it is not seen in the plane ofFIG. 3. An aperture 56 in the case wall 43 receives the CV output shaft57 of an associated axle. The peripheral wall 44 has a set of throughholes 58 alignable with the mounting holes 38 in the backing plate 11.Internally threaded holes 59 are provided in the peripheral wall 44 atmid-height. All of the holes 58, 59 have an integral concentric boss 60extending outwardly of the peripheral wall face 45.

The cover 42 is a flat plate proportioned to mate with the face 45 ofthe peripheral case wall 44. The cover has holes 62 that fit closelyover the bosses 60 and thereby register the cover with the case 41. Aninside face of the cover 42 is machined with recesses (FIG. 3) toreceive and support bearings 66, 67 in alignment with the recesses 51,52 in the case wall 43. The recess for the bearing of the gear 47 is notseen in the plane of FIG. 3. At an upper region, the cover 42 has aclearance hole 68 for receiving the outboard end of the CV shaft 57.Tapped holes 69 for screws (not shown) hold a cap 70 over the hole 68. Aclearance hole 71 in the cover 42 concentric with the bearing recess 67allows passage of an output shaft 72. At its outer face, the cover 42 isprovided with an elongated recess 73 for receiving a brake caliperbracket (FIG. 2). The bracket 74 has holes 75 that align with two of theholes 62 in the cover 42 and one of the holes 38 in the backing plate11.

The upper gear 46 is the input gear to the gear train or set. The gear46 has an internal spline cut to match the exterior spline on the CVoutput shaft 57 of the vehicle 5. The gear 46 has integral hollow stubshafts 77 on both of its sides. The stub shafts 77 are supported inbearings 53. An idler gear 47 has coaxial stub shafts 78 (only one isseen in FIG. 2) supported in bearings in the case wall 43 and cover 42.The output gear 48 is internally splined and fits on an external splineof the output shaft 72. The output shaft is rotationally supported inthe bearings 54, supported in the case wall 43 and cover 42. It will beseen that the centers of the input gear 46 and output shaft 72 arevertically aligned so that a wheel 12 mounted on the output shaft isdropped vertically from the original vehicle axle represented by the CVoutput shaft 57. Moreover, the pitch diameter of the output gear 48 issubstantially larger than the input gear 46 so as to multiply the torqueavailable at the output shaft 72.

The cover 42, case 41, and backing plate 11 are held together by bolts81 assembled through respective holes in these components. Commerciallyavailable seals (not shown) are provided at the case wall aperture 56and the cover hole 71 to exclude dirt, dust, and to contain lubricantwithin the case 41. A gasket is provided between the cover 42 and caseface 45; similarly, a gasket is provided between the cap 70 and cover42. An internally splined wheel hub 82 is retained on an external splineof the output shaft 72 by a nut 83 threaded on the distal end of theoutput shaft.

The portal boxes 10 on the left front and left rear axles are identical;the front and rear portal boxes 10 on the right side are identical toeach other and are mirror images of the portal boxes on the left.Internally, the gears 46-48 are identical on the left and right sides ofthe vehicle 5.

It is expected that the disclosed portal box system can be used with avariety of popular light off road vehicles offered by differentmanufacturers. The portal boxes 10 are readily adapted to the vehiclesby providing suitable brackets as substitutes for he disclosed brackets16, 17, 26, 29, and 31 or their equivalents, that can mate with thesuspension arms of a particular vehicle. The backing plate 11 isexceptionally versatile since it can accept essentially any suspension,steering and stabilizing bracketry existing on a particularmanufacturer's vehicle.

It should be evident that this disclosure is by way of example and thatvarious changes may be made by adding, modifying or eliminating detailswithout departing from the fair scope of the teaching contained in thisdisclosure. The invention is therefore not limited to particular detailsof this disclosure except to the extent that the following claims arenecessarily so limited.

What is claimed is:
 1. A portal box assembly for mounting a wheel of anoff road vehicle comprising a steel backing plate and a portal box, thebacking plate being formed of a flat plate and provided with a flatmounting surface and a pair of vertically spaced mounting bracketsextending away from the mounting surface, the brackets including holesfor connection with the suspension of a vehicle, the portal box andbacking plate having aligned holes for receiving bolts for mounting theportal box to the backing plate, the portal box containing input, idlerand output gears, the portal box having an operational orientation inwhich the output gear is below the input gear, the mounting bracketsbeing separately formed prior to mounting onto the backing plate.
 2. Aportal box assembly as set forth in claim 1, wherein the portal boxincludes a case that abuts the backing plate and provides a cavity forreceiving said gears.
 3. A portal box assembly as set forth in claim 1,including a cover plate, the cover plate being arranged to hold bearingsfor rotational support of said gears.
 4. A portal box assembly as setforth in claim 3, wherein said cover plate includes provisions forreceiving a brake caliper bracket.
 5. A portal box assembly as set forthin claim 3, wherein said case and cover plate have mating planar facesparallel to said backing plate.
 6. A portal box assembly as set forth inclaim 5, wherein said case is machined from an aluminum block.
 7. Aportal box assembly as set forth in claim 6, wherein said block is arectangular parallelepiped.
 8. A portal box assembly as set forth inclaim 1, wherein the mounting brackets are welded on the backing plateat locations determined by a vehicle on which the portal box isinstalled.
 9. A portal box assembly as set forth in claim 1, whereinsaid backing plate has a clearance hole for an output spline of a CVjoint.
 10. A portal box assembly as set forth in claim 9, wherein theclearance hole lies within an imaginary boundary defined by said alignedholes and said backing plate.
 11. A portal box assembly as set forth inclaim 3, wherein said case includes recesses carrying bearings forsupporting said gears.
 12. A portal box assembly as set forth in claim1, wherein said input gear has an internal spline for receiving anexternal spline of a CV joint of a vehicle axle.
 13. A kit for raisingand increasing wheel torque of an off road four wheel vehicle comprisingfour portal boxes, each portal box being associated with an individualone of the vehicle wheels, the portal boxes enclosing identical gearsets and associated bearings, each portal box being adapted to receivethe output of an axle constant velocity joint and having an output shaftprojecting therefrom, a set of four metal backing plates for joining theportal boxes to the suspension arms of the vehicle, the backing platesbeing substantially identical, the backing plates each having inwardlyextending mounting brackets for attaching to upper and lower suspensionarm parts.
 14. A kit as set forth in claim 13, wherein the mountingbrackets of one side of the vehicle are mirror images of the mountingbrackets of the other side of the vehicle.
 15. A kit as set forth inclaim 13, wherein said mounting brackets are welded on said backingplates.
 16. A kit as set forth in claim 13, wherein said portal boxesand backing plates have alignable bolt holes for receiving bolts thathold the portal boxes on the mounting plates.
 17. A kit as set forth inclaim 16, wherein said portal boxes include a hollow case and a coverplate, common bolts holding said cover on said case and said portal boxto said backing plate.
 18. A kit as set forth in claim 13, wherein saidportal boxes and backing plates have similar profiles with edgesaligning with an imaginary rectangle.